Deep South Winterwx Discussion 2015-2016

[Brent]

Hmmmmm... not at all getting that interested yet though.

ABC 33/40:

The computer models are in agreement on the overall pattern, with upper-level impulses approaching a weak front over the Gulf, forming a low pressure area near the Gulf coast Sunday night or Monday. This will bring precipitation to the southeast U.S., and likely snow for some areas. It’s still 5 days away, so a lot could change, but if the consensus of the models is right, this is the classic snow setup for Alabama (see blog from last week on this setup here.) The big question is: what part of Alabama?

The 12Z GFS, Canadian, UKMET, ECMWF, and NOGAPS models are in. The track of the low pressure center is critical. If the low is just south of the coast, from south of New Orleans to Tallahassee, the best chance for significant snow would be in Birmingham. This is roughly the scenario in the NOGAPS (except a little farther south) and the UKMET (a little farther north). The Canadian and the GFS show the low moving a little bit more north of the classic track for BHM, placing the heaviest snow in the Tennessee Valley. The ECMWF takes the low on a more northerly track, from the Gulf through Alabama…that would bring the snow more to Mississippi and west Tennessee. Model data is shown below.
One thing to point out…the GFS (and some other models) show this low really intensifying once it forms on Monday, with a favorable location relative to two jet streams aloft. So, somebody in the U.S. could get a lot of snow out of this one, and there will be a lot of cold air coming in on the back side of it. If the low is intense as forecast by some models, accumulating snow would fall as far south as BHM even if the track is a little too far north for us to be in the main snow band. For example, if the GFS is correct, parts of southern Tennessee and extreme north Alabama could get over 8″ of snow, but the snow could linger long enough for central Alabama to have 1-3″ accumulations.

These are all computer models, and everything could change by tomorrow (no Gulf low at all). And, even if the models stay on their current course, we don’t know if this will be a major event in BHM, or even in HSV. But, it is possible that the northern half of Alabama could get its first significant, widespread snow since 2000, so it’s one to watch for sure.

[Brent]

NWS BMX:

NEXT FORECAST HEADACHE BECOMES THE GULF LOW FORECAST TO IMPACT THE
REGION STARTING SUNDAY NIGHT AND LASTING INTO TUESDAY MORNING. THAT
LOW HAS SHOWN UP IN BOTH THE GFS AND ECMWF MODELS FOR AT LEAST THE
LAST COUPLE DAYS. HAVING SAID THAT...THE EXACT "FLAVOR" OF GULF LOW
VARIES GREATLY BETWEEN THE MODELS...AND (AS WOULD BE EXPECTED) AMONG
ITS OWN ENSEMBLE MEMBERS. NOW IS NOT THE TIME TO GET SUCKED INTO THE
CURRENT (12Z) GFS SOLUTION...WHICH WOULD LIKELY LEAD TO MULTIPLE
INCHES OF SNOW FOR SOME PLACE IN THE NORTHERN HALF OF THE CWA. BUT I
THINK IT IS NOW PRUDENT TO AT LEAST MENTION THE POSSIBILITY OF SNOW
IN THE FORECAST GRIDS...AS WELL AS THE HAZARDOUS WEATHER OUTLOOK
(ESPECIALLY CONSIDERING THE 12Z ECMWF HAS TRENDED TOWARD A STRONGER
AND MORE PHASED SYSTEM THAN IT PREVIOUSLY ADVERTISED). SO...LIKE MY
NEIGHBORS TO THE NORTH...I WILL GO WITH A RAIN OR SNOW TYPE WORDING
FOR (ROUGHLY) THE NORTHERN HALF OF THE CWA...AND WE CAN ADJUST AS
NEEDED AS THE MODELS (HOPEFULLY) START TO LOCK INTO A MORE DEFINITE
SOLUTION.

.MONDAY...CLOUDY. RAIN LIKELY AND A CHANCE OF SNOW. HIGHS IN THE
MID 40S. CHANCE OF PRECIPITATION 70 PERCENT.
.MONDAY NIGHT...PARTLY CLOUDY. BREEZY AT TIMES. A CHANCE OF RAIN
OR SNOW IN THE EVENING. LOWS IN THE UPPER 20S. CHANCE OF
PRECIPITATION 30 PERCENT.

[MGC]

Sure do hope this gulf low forms and give us and the SE USA some rain. Seems like there have not been many gulf lows as usual form the past couple of winters.....MGC

[Brent]

Sure do hope this gulf low forms and give us and the SE USA some rain. Seems like there have not been many gulf lows as usual form the past couple of winters.....MGC

Rain? It rained today. Screw the rain.

[DESTRUCTION5]

Looks like a massive storm for the SE to NE....Maybe the Storm of Winter 2009?

[Valkhorn]

For us in Knoxville this could mean all rain if it tracks to the east of the mountains or all snow if it tracks through the piedmont or near Asheville or Hickory, NC.

So far on the GFS it's been progging anywhere from 4 to 8 inches with parts in the Cumberland plateau or mountains getting over a foot.

The JMA model (sorry I don't have a link) is putting 12-14 inches near Chattanooga.

This has 'winner' written all over it - and I'm not saying it'll be anywhere near the March superstorm BUT it does share the fact that the 1993 superstorm was hinted at over 5 days out and this has been showing up consistently as well.

We shall see but I know this - I better make the trip to Kroger on Saturday morning.

[Daktar]

I live North of Knoxville in the union county area..After moving to TENNESSEE from the Gulf Coast I have been very disappointed in the amount of snow fall in this area.. This is my third winter and I have seen no more than an inch of snow during an event.. I have been told that if the system comes out the north or west it will always be lite amounts.. I was told that if it comes out the south to south west it is always a big dumping of snow in the Tennessee valley. I am as all the other snow hounds looking at the models and listening to all the providers of data.
I feel at this time I will keep it all to HYPE. We all know looking at models father out then 84 hours is a crap shoot.. How cold will the air be? will a low form? what will be the track of the low if it does form? will the low bomb out? will the surface low phase? Just a few factors that can an will change the forcast for many..
I hope for a blizzard however i will be lucky to see a flurry.

[breeze]

I'm in southern mid-TN, and I've been watching the models
and reading the thoughts on this potential storm, and,
well...since it's too early to hit the garden yet,
may as well Bring It On!

[One Eye]

Hopfully your luck will change Daktar. The position and strength of the low as you know can mean feast or famine. But you have to be encouraged by the latest model runs. If the GFS verifies, here in Vancleave, Ms could see a brief change over to light snow before the moisure ends. However as you know a winter storm on the gulf coast is usually a cold rain.

[Tampa Bay Hurricane]

The last two frames of 138 and 144 hr 18Z GFS show
the freeze line just south of Tampa Bay with rain...that would
be snow... I don't think that will verify...SNOW in tampa bay...GFS is
having some wild fantasy

[Brent]

ABC 33/40:

MONDAY: I always encourage you to watch the Weather Xtreme video we produce, which provides all of the graphics associated with this discussion. As I wrote on the midday update, I am not that interested in run to run variance right now… but taking more of an ensemble approach with potential winter storms like this.

The global models (GFS and Euro) have been trending northward with the surface low and the jet structure in the last 24 hours. The 12Z runs continue to hint the best chance of snow Monday will come from Tupelo to Muscle Shoals to Nashville, with a cold rain to the south. The rain could change to snow Monday night all the way down to Montgomery before ending, but with little accumulation down this way. Remember, this is not a forecast, simply model output. It is way too early to make a call on this storm, in terms of specifics.

The heaviest snow Monday could be as far north as Louisville, or as far south as Montgomery. It might be Huntsville or Birmingham. We simply don’t know yet. I will make a “first call” forecast here on the blog on the afternoon discussion as there will be reasonable skill at that time.

As the low deepens and moves northeast of Alabama on Tuesday, some folks around the Appalachians, and points west, could have a blizzard on their hands. For now it looks like the big snow event will be west of the major east coast cities.

One thing is for sure; Tuesday looks very cold; the GFS suggests we will stay in the 20s all day Tuesday with a chance of flurries in the moisture wrapping around the back side of the departing and deepening storm.

BOTTOM LINE: Too early to make a specific forecast call, but some folks around the Southeast U.S. should have a major snow event on their hands Monday. Stay tuned…

[hcaeb]

Brent,
You talk about SE - what do you see for North Carolina. Also, I always heard an inch of rain = 12" snow. What are your early forecast thoughts.

[Stormcenter]

This is an excerpt from this afternoon's (1-29-09) NWS New Orleans afternoon discussion. If memory serves me well the same thing was said in Dec. before the snow event in New Orleans about "not supporting any accumulations". It should be an interesting start to next week.

LONG TERM...
MOISTURE WILL RETURN RAPIDLY ON SUNDAY WITH RAIN BEGINNING SUN EVENING OR OVERNIGHT. A SFC LOW DEVELOPS OVER THE NW GULF AND MOVES EASTWARD OVER THE NORTHERN GULF BY MON MORNING. STRONG TO SEVERE TS ARE EXPECTED WITH THIS SYSTEM MANLY OFFSHORE. SOME OF THESE COULD STRAY JUST ONSHORE OF A FEW COASTAL PARISHES. A STRONG UPPER TROUGH WILL DIG INTO THE DEEP SOUTH BRINGING LOWERED HEIGHTS AND A STRONG COLD AIR SURGE DURING THE DAY MONDAY. AS THE LOW AND TROUGH BEGIN TO LIFT OUT...SOME MOISTURE STAYS BACK OVER THE AREA IN THE BASE OF THE TROUGH. A SECOND STRONG VORT MOVES DOWN THE BACK SIDE OF THE TROUGH AND WILL LIFT THE AVAILABLE MOISTURE BY LATE MON EVENING. SOME THICKNESSES AND SOUNDING PROFILE ARE HINTING AT A COLD ENOUGH COLUMN TO PRODUCE FLURRIES MON NIGHT. THIS IS STILL 4 DAYS OUT AND DIFFERENT SCENARIOS WILL BE POSSIBLE BUT IF THIS SCENARIO PLAYS OUT MOISTURE THICKNESS IS NOT SUPPORTING ANY ACCUMULATIONS.

[Brent]

Brent,
You talk about SE - what do you see for North Carolina. Also, I always heard an inch of rain = 12" snow. What are your early forecast thoughts.

What part of NC? The mountains near the TN border could get buried with MUCH less amounts east of there, with Raleigh and points east seeing much if any snow, but of course, things can change dramatically.

NWS Birmingham:

AND THEN THERE IS THE STORM SYSTEM FORECAST TO ARRIVE SUNDAY NIGHT
INTO MONDAY. CONFIDENCE IS PRETTY HIGH THAT THIS WILL BE A
RELATIVELY HIGH IMPACT EVENT...AS MODELS HAVE LOCKED ONTO SOME
VERSION OF A GULF LOW SCENARIO FOR AT LEAST A COUPLE OF DAYS NOW.
THE OBVIOUS BIG QUESTION REMAINS THE POTENTIAL FOR CHANGEOVER TO
SNOW BEFORE THE DEEP MOISTURE MOVES OUT. GIVEN THE 12Z RUNS OF
BOTH THE GFS AND ECMWF...I AM NOW FAIRLY CONFIDENT OF A RAINY
MONDAY MORNING...AND TEMPS BECOMING COLD ENOUGH FOR SNOW AFTER
DARK ON MONDAY EVENING. BUT CENTRAL ALABAMA REMAINS RIGHT ON THE
CUSP OF WHETHER OR NOT THE COLD AIR ARRIVES BEFORE THE STEADY
PRECIP MOVES OUT. SO...HAVING SAID THAT...I HAVEN`T CHANGED A LOT
FROM THE PREVIOUS FORECAST. I DID RAISE POPS INTO THE LIKELY
CATEGORY AREAWIDE ON MONDAY. RAIN LIKELY MONDAY MORNING...AND THEN
ADDING A CHANCE OF SNOW WITH THE RAIN LIKELY IN THE NORTH HALF
MONDAY AFTERNOON. I WILL ALSO KEEP SMALLER POPS INTO MONDAY NIGHT
(CHANCE OF SNOW). BOTH MODELS ALSO HINT AT SOME POST-SYSTEM
WRAPAROUND COLD AIR STRATUS SNOW FLURRIES OR SHOWERS ON TUESDAY...
SO KEPT THAT IN AS WELL. EVEN WITHOUT ANY SNOW ON TUESDAY...IT
STILL LOOKS LIKE A COLD AND BLUSTERY DAY.

[CYCLONE MIKE]

This is an excerpt from this afternoon's (1-29-09) NWS New Orleans afternoon discussion. If memory serves me well the same thing was said in Dec. before the snow event in New Orleans about "not supporting any accumulations". It should be an interesting start to next week.

LONG TERM...
MOISTURE WILL RETURN RAPIDLY ON SUNDAY WITH RAIN BEGINNING SUN EVENING OR OVERNIGHT. A SFC LOW DEVELOPS OVER THE NW GULF AND MOVES EASTWARD OVER THE NORTHERN GULF BY MON MORNING. STRONG TO SEVERE TS ARE EXPECTED WITH THIS SYSTEM MANLY OFFSHORE. SOME OF THESE COULD STRAY JUST ONSHORE OF A FEW COASTAL PARISHES. A STRONG UPPER TROUGH WILL DIG INTO THE DEEP SOUTH BRINGING LOWERED HEIGHTS AND A STRONG COLD AIR SURGE DURING THE DAY MONDAY. AS THE LOW AND TROUGH BEGIN TO LIFT OUT...SOME MOISTURE STAYS BACK OVER THE AREA IN THE BASE OF THE TROUGH. A SECOND STRONG VORT MOVES DOWN THE BACK SIDE OF THE TROUGH AND WILL LIFT THE AVAILABLE MOISTURE BY LATE MON EVENING. SOME THICKNESSES AND SOUNDING PROFILE ARE HINTING AT A COLD ENOUGH COLUMN TO PRODUCE FLURRIES MON NIGHT. THIS IS STILL 4 DAYS OUT AND DIFFERENT SCENARIOS WILL BE POSSIBLE BUT IF THIS SCENARIO PLAYS OUT MOISTURE THICKNESS IS NOT SUPPORTING ANY ACCUMULATIONS.

Stormcenter, this as you posted earlier today, is the second afd mentioningthis in a row. Even TWC has started talking about this potential as well. I am not holding my breath though. Seems as of now if the storm were to develop it will move out to quick before the cold air has a chance to build in. Our forecast is for rain early monday with highs in 50's then partly cloudy monday night lows in upper 20's. I know things can and probably will change this weekend. Would not surprise if low is a lot weaker if it forms at all. Anyway so far this winter snow has been mentioned quite a few times 4-5 days out only for nothing to happen with temps a lot warmer than forecast. Guess I just have to see it to believe it.

[Brent]

GFS continues to trend west and weaker with the initial storm but there's a secondary system that comes through Tuesday Night and drops snow around here. Either way it will be very cold behind the system. 0 C line down to the Keys at 138!

[breeze]

I guess a bit of humor helps as well, eh? Here's the latest from Nashville NWS office:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
922 PM CST THU JAN 29 2009



...OTHERWISE...MAIN FORECAST FOCUS WILL BE POTENTIAL WINTER STORM FOR
THE REGION MONDAY AND TUESDAY. ALTHOUGH WE MUST ALWAYS THROW IN
THE USUAL DISCLAIMERS ABOUT THE TRACK OF THE LOW..EXACT
TIMING...BLAH BLAH BLAH...IT PLEASES ME TO SAY THAT THE UPCOMING
SITUATION LOOKS LIKE A GOOD SETUP FOR ACCUMULATING SNOW. EVEN THOSE
WHO DO NOT LIKE SNOW (SHAME ON YOU) WILL HAVE TO ADMIT THE MODELS
HAVE BEEN PRETTY CONSISTENT SHOWING THE DEVELOPMENT OF THE
UPCOMING STORM AND THE POTENTIAL FOR REAL SNOWFALL IN MID TN. WILL
EVERYTHING COME TOGETHER FOR A REAL SNOWFALL EVENT IN MID TN? TOO
EARLY TO TELL...BUT ALL MODELS SHOW ACCUMULATING SNOW OVER THE
AREA INCLUDING ALL MEMBERS OF GFS ENSEMBLES. THE 18Z GFS SHOWS BNA
GETTING BLASTED WITH ABOUT 9 INCHES OF SNOW. THAT WOULD ONLY BE
-removed- AT THIS POINT...BUT IT/S FUN TO IMAGINE...AND WE ARE
CERTAINLY DUE! I PERSONALLY THINK THIS ONE WILL PAN OUT WITH AT
LEAST A FEW INCHES OF SNOW. BUT IF IT DOESN/T...AT LEAST WE CAN
ALL ENJOY THE UPS AND DOWNS OF EACH NEW MODEL RUN...AND WE CAN
SHARE THAT UNIQUE SOUTHERN BONDING EXPERIENCE OF FIGHTING FOR THE
LAST MILK AND BREAD ON THE SHELVES AS THE STORM APPROACHES.

&&

[Brent]

I dunno about this storm, GFS continues to trend weaker each run. But BRUTAL cold pours in following the storm. Could be even colder than a couple of weeks ago.

[Stormcenter]

This is third time in a row the NWS out of New Orleans, LA ( 1-30-09 am discuss.)mentions the possibility of frozen precip on Monday. The wording is a lot stronger this time around.

LONG TERM...
MODELS LOOK QUITE SIMILAR AGAIN THIS MORNING IN TERMS OF SFC AND
UPPER LEVEL TROUGH EVOLUTION THROUGH THE MIDDLE OF NEXT WEEK. BEGAN
INTRODUCING SCHC POPS EARLY SUNDAY MORN ALONG THE ATCHAFALAYA RIVER
PARISHES. SHOWERS SHOULD PROGRESSIVELY INCREASE FROM WEST TO EAST
THROUGH THE DAY ON SUNDAY AS SFC LOW DEVELOPS JUST OFF THE GULF COAST
SOUTH OF THE SABINE RIVER. THIS LOW IS PROGGED TO SKIRT THE COAST AS
IT TRACKS EASTWARD SUNDAY NIGHT. ATTM...LOOKING FOR MODERATE TO
HEAVY RAINFALL WITH THE HIGHEST AMOUNTS ALONG THE COASTAL PARISHES.
MAY NEED TO EXPAND THE HIGHER POPS FARTHER NORTH IF COVERAGE LOOKS
TO BE MORE WIDESPREAD. UPPER LEVEL TROUGH WILL BEGIN DIGGING
SOUTHWARD SUNDAY NIGHT...SENDING A COLD FRONT THROUGH THE AREA BY
THE MONDAY MORNING. THUNDERSTORMS STILL APPEAR TO BE POSSIBLE ALONG
THE COASTAL WATERS AND POSSIBLY IN THE NEAR SHORE PARISHES OF LA. A
FEW STORMS COULD BECOME STRONG BUT NOT EXPECTING SEVERE AT THIS
TIME. THICKNESSES WILL DROP CONSIDERABLY AS THE BASE OF THE TROUGH
SWINGS THROUGH MONDAY EVENING. A FEW LIGHT SHOWERS ARE EXPECTED TO
STILL BE LINGERING ACROSS THE AREA DURING THIS TIME. BASED ON
ANALYSIS OF MODEL SOUNDINGS AND 285K ISNTRPC LIFT...LOOKS LIKE IT
WILL BE A SHORT PERIOD OF SLEET AND THEN SNOW. DRY SLOT IN THE MID
LEVELS WILL LIKELY PREVENT ANY SIGNIFICANT PRECIP. SO NO
ACCUMULATIONS ARE EXPECTED AT THIS TIME BUT WILL LIKELY SEE FLURRIES
AND POSSIBLY A FEW LOCATIONS HAVING A LIGHT DUSTING ON GRASSY AREAS.
FROZEN PRECIP AREA SHOULD BE ALONG AND NORTH OF A MCB TO GPT LINE.

[Brent]

Further south but also much weaker, no major event anymore: